There are currently no rapid and reliable in vitro assays that measure the metastatic activity of cells. In this SBIR project, we propose to develop an improved Boyden chamber chemoinvasion assay, which will utilize Transwell (TM) membranes with a defined basement membrane overlayer that will allow in vitro assays for metastatic cells to be conducted with greater speed, reproducability, and sensitivity than existing assays. The chemoinvasion assays evaluate the invasive activity of metastatic cells by quantitating their ability to respond to a chemoattractant by penetrating a layer of reconstituted basement membrane (RBM). Several recent papers which utilize Matrigel (TM) as an RBM preparation have shown that this assay can be conducted in 6 hours and clearly discriminates between invasive and non-invasive cells. However, there is considerable assay variability, which is caused by: l) variability in the Matrigel overlayer and 2) poor adherence of Matrigel to the polycarbonate membrane (resulting in gaps through which non-metastatic cells can migrate). During Phase I, patented BSI photochemistry will be used to covalently couple type IV collagen and heparin onto the polycarbonate membranes with the expectation of greatly improving the adherence of RBM to the membrane. Also, initial experiments will be conducted to develop a defined RBM preparation to replace Matrigel. Modified polycarbonate membranes overlaid with Matrigel and defined RBM compositions will be evaluated with metastatic and non-metastatic cell lines. Phase II studies will complete the development of a defined RBM preparation.